The present invention relates to high speed datapaths, sometimes including mixed digital and analog voltage signals. In particular, it relates to error checking strategies for large data volumes, in digital and/or analog domains and to analog signal patterns that accelerate charge loading of micromirrors in an SLM.
A microlithographic direct writing system produces a very large data flow. Segments of the data path are not readily susceptible to error detection and correction, either because of the sheer data volume or because of the data format, such as an analogue output of a D/A converter. A direct writing system might include a positioning system for a workpiece, such as a wafer, on which a pattern is written. The writing begins with input pattern data that describes the pattern. A graphic data processing system with data storage and computing mechanisms converts transfer this data to a pattern exposure system that actually projects the image onto the workpiece. One direct writing system could be based on Micronic Laser System's SLM-based patterning platform for mask writing. An SLM is a spatial light modulator that includes a large array of small mirrors that are individually controlled by analog voltages output from D/A converters. A laser flash is relayed from the micromirror array to an image plane, where it exposes a pattern on the workpiece. When the flash is generated, the array of micromirrors is actuated in a state that represents an image element. The laser typically flashes at a rate of a few kilohertz. The number of micromirrors in an array is typically one to four million. The amount of data required to drive the micromirrors is very large and the required data transfer rate is very high.
It is difficult to preserve data reliability through the data-path to the exposure mechanism. Data reliability in this context means preserving data integrity so no pattern data information is lost or changed in a way that is not intended. The preservation of data integrity in the data path needs separate mechanisms applicable to digital data storage, digital data transfer, digital data manipulation, digital to analog data conversion and analog data transfer.
An opportunity arises to improve data reliability methods and mechanisms. Better, more trustworthy and reliable components and systems may result.